Northstar Engines and System Technical Discussion Discussion, Tricky Coolant Leak in Cadillac Engine Technical Discussion; Hrmnn I have a coolant leak and can not find it. I really hope its not the heater core but ...

Tricky Coolant Leak

Hrmnn I have a coolant leak and can not find it. I really hope its not the heater core but I dont smell coolant in the car... I'm really lost this one, just when you think you know a lot you know nothing. Okay I know what area its coming from but where. I'm thinking its dripping in a different place sliding down a tie rod or something lol, i have no clue..

The coolant is leaking from the driver side of the car behind the tire. I checked under the car and it apprears to be leaking from the corner of the rear front left fender where the ground effect piece is.

So the Fender is leaking coolant? WTF?

it is a slow. Leaks about half of a quart every 2 weeks and its only been 2 weeks. The low coolant indicator only came on once.

A thing that had me worried which is probably normal but with the head threads corroding on the n*'s is I still had pressure in the coolant resevor after 3 hours of the car being turned off and coolant temp at 110 Degrees.

I had a poof when i removed the cap which i really hope is coolant pressure and not from the motor. So im thinking i have pressure and a leak. what gives if im leaking it would piss more or alot. I really hope this isnt the heads loosening up.

Re: Tricky Coolant Leak

Crossover would probably drip somewhere near the engine-transmission joint line. Dripping from the wheel/fender area sounds like the lower hose fitting or the level sensor boss on the surge tank is cracked and the coolant is running down the fender sheet metal.

Also, take a strong flashlight and look at the firewall coupling for the heater core lines and then trace them back to the water pump/thermostat housing area.

Re: Tricky Coolant Leak

The leak is coming from the drivers side pretty much where the door meets the fender. on mine the surge tank is on the passengers side. The heater core i think is more on the passengers side thats why im so stumfed. I guess ill have to pull the shield off jack the car way up, get a hand mirror and get down and dirty and find it?? havent really got down and dirty with it yet just shoved my head under and in the engine compartment to take a look. I think its going to be hard to find because its such a slow leak, hasnt really got worse but snow is coming so i cant work on it then,.

Re: Tricky Coolant Leak

Check the metal heater tubes that run around the rear of the engine from the crossover pipe all the way over to the heater core. They are way down low on the rear of the engine just below the cam cover/head mating surface. They corrode pretty badly over time and leak.

Re: Tricky Coolant Leak

Originally Posted by Mark C

Check the metal heater tubes that run around the rear of the engine from the crossover pipe all the way over to the heater core. They are way down low on the rear of the engine just below the cam cover/head mating surface. They corrode pretty badly over time and leak.

I second that motion. Very tough to change - some have bypassed them with hoses

Re: Tricky Coolant Leak

Found my slow leak, I pulled the wheel well out, etc and there was a plastic cap in the fender pulled that and water poured out. So it wasn't coolant. MY fender was filed with water and slowly dripping, There was a greasy grime plugging the bottom of the windshield drain passage.

I think my coolant leak was on the reservoir (auto-bleed) return line, there was a leak down the resevor. VERY SMALL. it was a dry stain, looked like a white crud. I think that could be the prob. I cut the hose down and reclamped it. Still waiting for that damn coolant level low indicator to come back on. Hopefully I fixed it.

Re: Tricky Coolant Leak

I have an odd coolant leak too. Intermittent..but gotten worse lately. coming from backside of engine..midway. whne its leaking..will still have pressure after a while. I finally broke down and got some coolant tabs. Put them in the lower radiator hose today..topped off with Dex-Cool. Prob put about 100 miles on after....dry so far. We'll see.